Dual-purpose incandescent lamp



Feb. 4, 1958 F. D. ALBRIGHT DUAL-PURPOSE INCANDESCENT LAMP Filed Marh 24. 1954 ZmnemorVv Pfade/ick .Z2 AZ/"fy// United States Patent O DUAL-PURPOSE INCANDESCENT LAMP Frederick D. Albright, Bridgeport, Conn., assigner of one-half to Patsy F. Fiorito, Bridgeport, Conn.

Application March 24, 1954, Serial No. 418,333

12 Claims. (Cl. 313-111) This invention relates to incandescent electric lamps, and more particularly to dual-purpose electric lamps capable of selectively providing a white beam and at least one colored beam.

The invention has special utility in connection with vehicle lighting, as for example in providing a combined headlight and fog lamp, or a combined tail light or stop light and backing-up light. However, it should be understood that the invention is not limited to these specific applications, since it has general utility wherever white and colored beams are to be provided from a single lamp. The scope of the invention is therefore not to be restricted to the specific embodiments thereof described and illustrated herein, but is more properly taken in connection with the appended claims.

Heretofore various lamp and lighting structures have been proposed by which white and different colored beams may be made to emanate from a single lamp. ln many of these prior constructions a single electric bulb is utilized in conjunction with various different reflectors or lenses to produce the different colored beams. In these arrangements the lenses or shades of different co1- ors were mechanically shifted into the path of the light rays, to produce the coloring of the beam. Such devices in general have not been feasible and practical because of the complicated mechanisms involved, the re1- atively high manufacturing cost, and the likelihood of the units developing trouble in use and getting out of order. Moreover, such constructions were susceptible to damage from the vibration commonly encountered in motor vehicles, and in some instances mechanically-controlled mechanisms were needed, requiring additional space and involving installation problems.

In another prior proposal there was provided a lamp and associated reflector, in conjunction with a pair of spaced frontal lens members between which colored particles could be suspended or maintained in motion. These colored particles imparted coloring and animation to the light beam, and when the particles were allowed to come to rest at the bottom of the enclosure, the light beam passed through the lens members without any coloring whatsoever. Such a system is undesirable in at least one respect in that it requires a source of compressed air to effect the agitation of the colored particles when it is desired to color the beam.

Still another prior proposal provided an incandescent electric bulb having a plurality of filaments one of which was surrounded by a small colored globe having at one end a lens. Electromagnetic means was provided for shifting the bulb to different positions, to bring into focusing position either the uncovered or the covered filament, thereby to eect a projection of either a clear beam or a colored beam. This arrangement not only has the drawback of additional mechanical and electrical components for effecting positioning of the bulb, but the colored globe imparted some of its color to the white bearn even though the device was properly Aadjusted for projection of only white light, with the ment providing the colored beam inactivated.

The disadvantages and drawbacks of these prior devices are obviated by the present invention, and an object of the invention is to provide an improved dualpurpose incandescent lamp capable of selectively producing a white beam and a colored beam, wherein the coloring means for the colored beam does not in any way affect the white beam.

Another object of the invention is to provide an improved dual-purpose incandescent lamp capableof producing white and colored beams, which is extremely simple and compact in its construction, and relatively economical to fabricate.

A still further object of the invention is to provide an improved and simplified dual-purpose incandescent lamp capable of producing white and colored beams, wherein no mechanically movable structures or members are required.

A further object of the invention is to provide an improved dual-purpose incandescent lamp in accordance with any of the foregoing, which is strong and sturdy in its construction and resistant to vibration and shock, and capable of an extended useful life.

Yet another object of the invention is to provide' an improved dual-purpose incandescent lamp vas above set forth, which is constituted entirely as a single, self-contained unit, adaptable as a replacement unit for existing lamps of vehicles, thereby avoiding the necessity for separate, special-purpose lamps for which mounting provision is sometimes not made, orif made, results in the lamp being unduly exposed to damage.

A still further object of the invention is to provide an improved combined headlight and fog lamp for a motor vehicle, characterized in accordance with the foregoing.

A feature of the invention resides in the provision of an improved dual-purpose incandescent electric lamp as above set forth, which is constituted of a single sealed unit of the type commonly known to the trade as a sealed beam unit.

Still another object of the invention is to provide an improved combined headlight and fog lamp for a vehicle as above disclosed, wherein both low and high, strong-intensity white beams are obtainable as well as a powerful amber-colored, fog-penetrating beam of'greater intensity than presently obtained from existing fog lights.

Another object of the invention is to provide an im-v proved and simplified unitary dual-purpose incandescent electric lamp unit capable of producing both clear and red beams and adaptable for use as a vehicle tail or stop light and backing-up light.

In accomplishing the above objects I provide a novel lamp structure which, in its essentials, comprises a front filament and a rear filament the latter being spaced an appreciable distance behind the front filament. I provide means, as for example a glass envelope, by which the filaments are surrounded by a ratified atmosphere. Behind the rear filament I provide a collecting reliector, adapted to direct light from the rear filament forward in a concentrated beam, In front of the front filament I provide a second and smaller collecting reflector, arranged to direct light from the front filament rearward in a concentrated beam against the rear reflector, to be redirected forwardly thereby.' In conjunction with the above'structure I provide means disposed adjacent the front filament for imparting color to the light emanating from said filament and the second reliector, said means being so arranged and constituted that it does not impart any color to the light emanating from the latented Feb. 4, 195.8A

filarear filament and which constitutes the source for the White beam of the lamp.

The above selective coloring means, in one embodiment of the invention, comprises a colored lens disposed in back of the front filament and having a rear silvered surface adapted to enable light from the second reflector and from the front filament to pass rearwardly through the lens but reflecting any light which might strike the lens from the rear lament. Since the light from the rear filament is thus prevented from passing through the colored lens it will not be colored thereby, and therefore the whiteness of the beam will not be affected by the coloring means of the colored beam component.

In another embodiment' of the invention I replace the silvered, colored lens by a lens-shaped hollow body having itsfront wall colored audits rear wall clear, and I introduce mercury into said body in'response to heating ofthe rear filament, thereby'to provide a reflecting means for light from said filament, preventing such light from passing through the front'colored Wall and being colored thereby.

In both embodiments of the invention the filaments and reflectors and coloring means are wholly enclosed in a. single evacuated glass envelope of the type used in sealed beam lamps.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure 1 is an axial sectional view of a dual-purpose incandescent lamp'made in accordance with the invention.

Fig. 2 is a fragmentary vertical sectional View taken on line 2-2 of Fig. 1.

Fig. 3 is an enlarged detail showing in vertical section the colored beam unit of the lamp.

Fig. 4 is an axial sectional view of a lamp constituting another embodiment of the invention.

Fig. 5 is an enlarged detail in vertical section, of the colored beam unit of the lamp of Fig. 4.

Fig. 6 is a perspective view of the interior structure of the lamp of Fig. 4.

Referring to Fig. 1, the improved dual-purpose incandescent lamp of this invention comprises an evacuated glass envelope 10 having a concavo-convex front wall portion 11 provided with the usual lens prisms 12 well knownto those skilled-in the art. The glass envelope 10 further comprises a parabolic-shaped rear wall 13r having its peripheral or lip portion 14 joined and sealed to the'peripheral portion 15 of the lens 11. On the inside of the rear wall 13 a reflecting surface 16 is provided, as by a flash-aluminum or other process currently practiced in the art.

The rear wall 13 of the envelope thus serves as a collecting reflector, being adaptable to reflect light from filamentary sources'within the envelope 10, and to direct said light forwardly through the front lens portions 11 ofthe envelope in the well known manner. The prisms 12 of the lens portion 11 may be so arranged as to greatly narrow the vertical spread of the light from the reflector 13 and to Widen the horizontal spread of the light, as is usual with headlight lamps. However, any of various prismatic contours may be provided on the front lens 11 to provide desired light patterns, either concentrated to the left or to the right, or made lower to the right when viewed from the front, as might be necessary to adapt the lamp to a particular application.

At the rear center portion of the reflector wall 13 a rearwardly-extended boss 13a is provided, surrounded by a thimble 17 which secures a terminal block 18 to the rear face of the boss. Electric terminals 19 are provided on the terminal block 1S and are attached to pairs of current-conducting bars or rods 20 and 21, the latter rods being relatively short and supporting respectively a highbeam filament 22 and a low-beam filament 23 located closely adjacent the focal point of the reflector 13. The

filaments 22 and 23 are secured to a current-conducting and supporting arm 24 which is attached to the upper one' of the rods 20. The filaments 22 and 23 are hereinreferred to as rear filaments, since they are disposed a substantial distance to the rear of another filament lo cated within the glass envelope 10, said other filament being herein referred to as a front filament.

In accordance with the present invention I provide a'v novel means within the glass envelope 10 by which the= lamp may be made to produce a colored beam indepen-l dently of the headlight filaments 22 and 23 while at the same time the said headlight filaments may function in the usual manner to produce a clear or white beam of light not affected by the coloring means for the coloring beam.

in accomplishing this I provide a front filament 25 in the glass envelope 1Q, disposed a substantial distance forwardly ofV the rear filaments 22 and 23. To support the front filament 25 the rods 2b are made to have considerable length and appreciable thickness for added strength, said rods having their foremost end portions 29a of slightly reduced diameter, with the extremities secured to the ends of the filament 2S to support the latter. l' prefer to locate the filament 25 in front of the plane which contains the peripheral or lip portion 14 of the reflector 13, although this is not absolutely essential to the proper functioning of the device.

In front of the front filament 25 I provide a second collecting reflector 26, preferably formed of metal which is opaque and having a dishlike shape with both front and rear reflecting surfaces 27 and 28. The reflector 26 is so designed and arranged that the front surface reflects light from the lens 11 forwardly, and the rear surface reflects light from the filament 25 rearward against the reflector 13 in a concentrated beam whereby' the latter reflector will reflect or redirect the light for wardly against and through the front lens 11 in a further# concentrated beam.

For the purpose of coloring the light which is reflectedy rearward by the reflector 26 I provide a colored lens 2 having a pair of openings through which the portions 20a of the filament supporting bars 20 pass. The lens 29 is thus supported by the bar portions 20a, and the periphery of the lens 29 is secured to the periphery of the reflector 26 to thereby support the latter in its proper position in back of the filament 25. It will be understood that light from the filament 2S, whether it be direct or reflected, passing through the lens 29 will be colored thereby, resulting in a colored beam beingiproduced by the lamp unit.

ln accordance with the invention I provide a means by which light from the filaments 22 and 23 will not be colored due to the presence of the colored lens 29, thus enabling the unit to produce a pure white beam. This means constitutes a light-passing mirror surface 30 on the rear face of the lens 2li. Such mirror surfaces are well known in the mirror art, and have the ability to reflect light striking them from one side while permitting light to pass through the mirror surface from its other side. in other words, these mirrors have light-reflecting faces and light-absorbing 'surfaces at the rear. By my construction the mirror surface 3f) will permit light from the filament 25 topassre'arwardly through the colored ens 29, but said mirror surface will reflect light passing forwardly toward it from the rear filaments 22 and 23.

Thus such light from the filaments 22 and 23 will not be colored by the lensr29, and only the light from the filament 25 will be so colored. I thereby obtain a selective incandescent lamp unit having no mechanically-moving parts or electromagnetic parts yet which is capable of producing either a colored light or a white light beam not having any coloring whatsoever. It is merely necessary to energize the proper filament to obtain either a white high beam, a white low beam, or a colored beam from the lamp structure shown in Figs. l through 3. If

the coloring imparted by the lens 29 is amber', then the lamp unit may be made to serve as an efficient fog lamp. Such a lamp unit is seen to be entirely self-contained as a sealed unit, similar to a sealed beam head lamp, to be devoid of moving parts which might get out of order, to be resistant to shock and vibration, and to be a direct replacement for existing sealed beam head lamps. The structure of my improved dual-purpose lamp is relatively simple, and the manufacturing cost is relatively low; moreover the lamp will have an extended useful life commensurate with that of existing sealed beam head lamps, such life for example often exceeding ten years of normal use.

The masses or weights of the reflector 26 and the lens 29, and of the filament 25 are relatively small, enabling these components to be readily sturdily supported within the envelope l0 by the bars 20, thus making for stability and reliability of performance.

The dual-purpose lamp of the present invention provides an extremely powerful and effective amber-colored fog lamp beam for the reason that the lamp diameter is relatively large, being of the conventional size commonly employed for headlights. This size is appreciably larger than the diameter of fog lights as presently produced, and therefore more useful light for the amber beam is obtained than with present fog lights. It is well understood that larger reflectors and focusing lenses, within limits, reduce stray or lost light and instead provide a greater utilization of the light available from a given filament.

By the provision of the combined headlight and fog light function in a single sealed beam unit there is obviated the necessity for special mountings of separate fog lights. In many instances, because of present day car design, no provision is made for mounting separate fog lights and as a consequence the sales of these units have fallen off considerably. Where the car design does permit mounting of a separate fog light, the location is often such that the light is unduly exposed to damage. These drawbacks are obviated by the present invention, and moreover by the elimination of separate fog lamps the car may have a cleaner design and appearance.

Another embodiment of the invention is shown in Figs. 4 through 6. In this embodiment components similar to those already described above have been given like characters. The main difference between the embodiment of Figs. l and 4 resides in the construction of the lens for the front filament 25. In Fig. 4 the filament and lens support rods are numbered 2Gb, 20c, and the front reflector 26a. This reflector has reflecting surfaces 27a and 28.1.'. Considering the coloring lens for the filament 25, this lens is made in the form of a hollow concave-convex body 32 having a front wall 33 which is colored and having a rear wall 34 which is clear or uncolored. The body 32 has a cavity 35 communicating with the bore 36 of a tube 37 forming a passage, said tube communicating with a reservoir 3S disposed adjacent and in front of the rear filaments 22 and 23. In the reservoir 3S mercury 39 is provided, and the arrangement is much like that of a thermometer and thermometer bulb. When the reservoir 3S has a relatively low temperature, the mercury 39 therein will be contracted and withdrawn from the cavity 35 of the lens 32. When the reservoir 38 and mercury 39 are heated, the expansion of the mercury will force it to occupy the cavity 35 of the lens 32. In this latter instance the mercury will act as a reflector in the lens body 32, reflecting all light passing forward from the filaments 22 and 23. Thus such light will be prevented from passing through the colored wall portion 33 of the lens, and this condition will exist whenever any one of the filaments 22 or 23 is incandescent. Therefore light from either of these two filaments, as it is projected from the lamp unit, will always be white and will not receive any coloring from the lens 32. However, when the filaments 22 and 23 are cold the mercury will be exhausted from the cavity 35 of the lens 32 and for such a condition energization of the front filament 25 will result in light therefrom passing rearward through the lens 32 and being colored thereby and thereafter reflected and redirected so as to emanate forwardly of the lamp unit as a colored beam.

The embodiments of the invention illustrated and described above comprise combined automobile head lamp and fog lamp units. However it will be obvious to one skilled in the art that combined tail light or stop light and backing-up light units may be constructed in a similar manner, using red colored lenses instead of amber colored lenses, and various other uses will also be suggested.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

l. A dual-purpose incandescent lamp comprising al front filament and a rear filament; means providing a rarified atmosphere around said filaments; a collecting reflector behind the rear filament, directing light therefrom forward in a concentrated beam; a substantially opaque collecting reflector in front of the front filament, directing light therefrom rearward in a concentrated beam against the rear reflector to be redirected forwardly thereby; a colored lens disposed in front of the rear filament and behind the front filament, for imparting color to the light emanating from the front filament; and means disposed between the rear filament and the said colored lens and providing substantially one way passage of light, operable to reflect backward light which is directed forward from the rear filament toward said lens when said filament is lighted, thereby to prevent the lens from coloring said light, said lens and opaque reflector and means providing one-way passage of light enclosing the said front filament.

2. A dual-purpose incandescent lamp comprising a front filament and a rear filament; means providing a rarified atmosphere around said filaments; a collecting reflector behind the rear filament, directing light therefrom forward in a concentrated beam; a substantially opaque collecting reflector in front of the front filament, directing light therefrom rearward in a concentrated beam against the rear reflector to be redirected forwardly thereby; a colored lens disposed in front of the rear filament and behind the front filament, for imparting color to the light emanating from the front filament; and means disposed adjacent said lens and between the latter and the rear filament, enabling light to pass rearwardly therethrough but reflecting light, which is directed forwardly toward said lens, away from the latter, said lens and opaque reflector and l-ast-named means enclosing the said front filament.

3. A dual-purpose incandescent lamp comprising a front filament and a rear filament; rarified atmosphere around said filaments; a collecting reflector behind the rear filament, directing light there-i from forward in a concentrated beam; a substantially opaque collecting reflector in front of the front filament,

directing light therefrom rearward in a concentrated beam against the rear reflector to be by; a colored lens disposed in and behind the front filamengfor imparting color to the redirected forwardly therelight emanating from the front filament; and means responsive to energization of the rear filament, providing a reflector at the rear of said lens for reflecting backward any light which is directed forward from said filament toward said lens, thereby to prevent coloring of said light, said lens and opaque reflector and last-named means enclosing the said front filament.

4. A dual-purpose incandescent lamp comprising a front filament and a rear filament; means providing a rarified atmosphere around said filaments; a collecting reflector behind the rear filament, directing light theremeans providing a front of the rear filament from forward in ,a concentrated beam; a substantially opaque collecting reflector infront ofthe front filament, directly-light therefrom rearward ina concentrated beam against the rear reflector to be redirected forwardly thereby; and means` comprising a curved lens disposed in front of the rear filament and in back of the front filament, for imparting color to the light emanating from the front filament, saidcurved lens and second-mentioned collecting refiector forming an enclosure for the front filament, and said curved lens having a screen at its rear, provided with a light-passing forward surface and 1a light-reflecting rearward face.

5. A dual-purpose incandescent lamp comprising a front filament and a rear filament; means providing a rarified atmosphere around said filaments; a collecting reflector behind the rear filament, directing light therefrom forward in a concentrated beam; `a substantiaily opaque collecting refiector in front of the front filament, directing light therefrom rearward in a concentrated beam against'the rear reector to be redirected forwardly thereby; Aand means comprising a curved lens disposed in front of the rear filament and in back of the front filament, for imparting color to the light emanating from the front filament, said curved lens and second-mentioned collecting reflector forming an enclosure for the front filament, said enclosure having -a vent to provide for free expansion and contraction of the gases surrounding the front filament, and said curved lens having a screen at its rear, provided with a light-passing forward surf-ace and a lightreflecting rearward face.

6. A dual-purpose incandescent lamp comprising a front filament and a rear filament; means providing a rarified atmosphere aro-und said filaments; a collecting reflector behind the rear filament, directing light therefrom forward in a concentrated beam, said refiector having its periphery disposed substantially forward of the rear filament and the plane of said periphery being disposed behind the front filament; a substantially opaque collecting reector in front of the front filament, directing light therefrom rearward in a concentrated beam against the rear reliector to be redirected forwardly thereby; and means disposed in front of the rear filament and in back of the front filament, for imparting color to the light emanating from the front filament, said means having a screen at its rear, provided with a light-passing forward surface and a light-reflecting rearward face, said screen and last-named means and opaque reflector enclosing the said front filament.

7. A dual-purpose incandescent lamp comprising a front filament and a rear filament; means providing a ratified. atmosphere around said filaments; a collecting refiector behind the rear filament, directing light therefrom forward in a concentrated beam; a substantially opaque collecting refiector in front of the front filament, directing light therefrom rearward in a 'concentrated beam against the rear reliector to be redirected forwardly thereby; a colored 4lens disposed in front of the rear filament and behind the front filament, for imparting color to the light emanating from the front filament; and means disposed adjacent said lens, enabling light to pass rearwardly therethrough but reflecting light which is directed forwardly toward said lens away from the latter, said means comprising a silvered surface on the back of the lens, said lensand opaque reflector and last-named means enclosing the saidfront filament.

8. A dual-purpose incandescent lamp comprising a front filament and a rear filament; means providing a rarified atmosphere around said filaments; a` collecting, reflector behind the rear filament, directing light therefrom forward in a concentrated beam; a substantiallyi opaque collecting reflector in front of the front filament, directing light therefrom rearward in a concentrated beam against the rear reflector to be redirected forwardly thereby; a colored lens disposed in front of the rear filament and behind the front lament, for imparting color to the light emanating from the front filament; and means responsive to energization of the `rear filament, providing a reflector at the rear of said lens for reflecting backward any light which is directed forward from said filament toward said lens, thereby to prevent coloring of said light, said means comprising a hollow lconcavo-convex body disposed at the rear of the front filament, the front wall of said body constituting the said colored lens, and said means further comprising mercury adapted to occupy the hollow body, said lens and opaque reflector and last-named means enclosing the said front filament.

9. The invention as defined in claim 8 in which there is a reservoir for said mercury, connected with the said hollow body and disposed adjacent the rear filament in front of the latter `and in heat-receiving relation with the same.

10. The invention as defined in claim 9 in which there is means providing a passage between the said hollow body and reservoir, said means, reservoir and hollow body being of integral construction.

l1. A dual-purpose lamp comprising a light source; a colored, translucent member adjacent said Vlight source, adapted to pass light therefrom and -color the same; a second light source disposed on the opposite side of said member from the first-mentioned light source; reflector means disposed between the second light source and the colored member, provided with a surface facing said second light source which is adapted to reflect light directed from said second light source toward said colored member, thereby to minimize the penetration of said member by said light and the coloring of said light, said refiector means having an opposite surface facing the first-mentioned light source which is capable of passing light from the said latter source; and a dishlike opaque reflector joined to the translucent member and reflector means and disposed about the first light source and adapted to concentrate light therefrom, said translucent member, first light source yand reflector means being between said dishlike opaque reflector and the second light source, said first light source being located between the central portion of the opaquevreector and the said translucent member in spaced relation thereto; and an evacuatedenvelope enclosing said light sources, translucent member, refiector means and opaque reflector.

l2. The invention as defined in claim 1l in which the means operable to refiect light comprises a mirror means on one surface of said colored member.

References Cited in the file of this patent UNITED STATES PATENTS 1,649,975 Parks Nov. 22, 1927 1,666,876 Price Apr. 17, 1928 1,923,181 Albers Aug. 22, 1933 2,398,971 Singer Apr. 23, 1946 

